And next tonight, a new mystery for the three brave women held captive in that house of horrors in cleveland. Michele knight, gina de jesus, amanda berry. Aerial castro found dead in his prison cell. Tonight, a new question, did prison guards secretly let it happen? Alex perez back on the story. Reporter: When aerial cast troe was innocenced to life in prison last august, one of his victims, michele knight confronted his abductor. I spent 11 years in hell. Now, aerial thinks it's a game. Reporter: A month and a day after he began serving his sentence, he was found hanging in his cell, now ohio state investigators say the guards assigned to castro lied how they handled him prior to his death. They were to check on him every 30 minutes. The report finds they missed at least eight required checks and falsified logs on the day he died. The report raises questions why it took 34 minutes from an balance to arrive at the prison. The medical examinered ruled it a suicide but still since his death, his attorney questioned why he wasn't watched more closely. He should have been on suicide watch. Reporter: Authorities are now launching a criminal investigate and the two guards at the center of it all are on administrative leave. Alex perez, abc news, chicago.

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